gcc/ipa-prop.h

   1 /* Interprocedural analyses.
   2    Copyright (C) 2005, 2007, 2008, 2009
   3    Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef IPA_PROP_H
  22 #define IPA_PROP_H
  23
  24 #include "tree.h"
  25 #include "vec.h"
  26 #include "cgraph.h"
  27
  28 /* The following definitions and interfaces are used by
  29    interprocedural analyses or parameters.  */
  30
  31 /* ipa-prop.c stuff (ipa-cp, indirect inlining):  */
  32
  33 /* A jump function for a callsite represents the values passed as actual
  34    arguments of the callsite. There are three main types of values :
  35
  36    Pass-through - the caller's formal parameter is passed as an actual
  37                   argument, possibly one simple operation performed on it.
  38    Constant     - a constant (is_gimple_ip_invariant)is passed as an actual
  39                   argument.
  40    Unknown      - neither of the above.
  41
  42    IPA_JF_CONST_MEMBER_PTR stands for C++ member pointers, it is a special
  43    constant in this regard.  Other constants are represented with IPA_JF_CONST.
  44
  45    IPA_JF_ANCESTOR is a special pass-through jump function, which means that
  46    the result is an address of a part of the object pointed to by the formal
  47    parameter to which the function refers.  It is mainly intended to represent
  48    getting addresses of of ancestor fields in C++
  49    (e.g. &this_1(D)->D.1766.D.1756).  Note that if the original pointer is
  50    NULL, ancestor jump function must behave like a simple pass-through.
  51
  52    Other pass-through functions can either simply pass on an unchanged formal
  53    parameter or can apply one simple binary operation to it (such jump
  54    functions are called polynomial).
  55
  56    IPA_JF_KNOWN_TYPE is a special type of an "unknown" function that applies
  57    only to pointer parameters.  It means that even though we cannot prove that
  58    the passed value is an interprocedural constant, we still know the exact
  59    type of the containing object which may be valuable for devirtualization.
  60
  61    Jump functions are computed in ipa-prop.c by function
  62    update_call_notes_after_inlining.  Some information can be lost and jump
  63    functions degraded accordingly when inlining, see
  64    update_call_notes_after_inlining in the same file.  */
  65
  66 enum jump_func_type
  67 {
  68   IPA_JF_UNKNOWN = 0,  /* newly allocated and zeroed jump functions default */
  69   IPA_JF_KNOWN_TYPE,        /* represented by field base_binfo */
  70   IPA_JF_CONST,             /* represented by field costant */
  71   IPA_JF_CONST_MEMBER_PTR,  /* represented by field member_cst */
  72   IPA_JF_PASS_THROUGH,      /* represented by field pass_through */
  73   IPA_JF_ANCESTOR           /* represented by field ancestor */
  74 };
  75
  76 /* Structure holding data required to describe a pass-through jump function.  */
  77
  78 struct GTY(()) ipa_pass_through_data
  79 {
  80   /* If an operation is to be performed on the original parameter, this is the
  81      second (constant) operand.  */
  82   tree operand;
  83   /* Number of the caller's formal parameter being passed.  */
  84   int formal_id;
  85   /* Operation that is performed on the argument before it is passed on.
  86      NOP_EXPR means no operation.  Otherwise oper must be a simple binary
  87      arithmetic operation where the caller's parameter is the first operand and
  88      operand field from this structure is the second one.  */
  89   enum tree_code operation;
  90 };
  91
  92 /* Structure holding data required to describe an ancestor pass-through
  93    jump function.  */
  94
  95 struct GTY(()) ipa_ancestor_jf_data
  96 {
  97   /* Offset of the field representing the ancestor.  */
  98   HOST_WIDE_INT offset;
  99   /* TYpe of the result.  */
 100   tree type;
 101   /* Number of the caller's formal parameter being passed.  */
 102   int formal_id;
 103 };
 104
 105 /* Structure holding a C++ member pointer constant.  Holds a pointer to the
 106    method and delta offset.  */
 107 struct GTY(()) ipa_member_ptr_cst
 108 {
 109   tree pfn;
 110   tree delta;
 111 };
 112
 113 /* A jump function for a callsite represents the values passed as actual
 114    arguments of the callsite. See enum jump_func_type for the various
 115    types of jump functions supported.  */
 116 struct GTY (()) ipa_jump_func
 117 {
 118   enum jump_func_type type;
 119   /* Represents a value of a jump function.  pass_through is used only in jump
 120      function context.  constant represents the actual constant in constant jump
 121      functions and member_cst holds constant c++ member functions.  */
 122   union jump_func_value
 123   {
 124     tree GTY ((tag ("IPA_JF_KNOWN_TYPE"))) base_binfo;
 125     tree GTY ((tag ("IPA_JF_CONST"))) constant;
 126     struct ipa_member_ptr_cst GTY ((tag ("IPA_JF_CONST_MEMBER_PTR"))) member_cst;
 127     struct ipa_pass_through_data GTY ((tag ("IPA_JF_PASS_THROUGH"))) pass_through;
 128     struct ipa_ancestor_jf_data GTY ((tag ("IPA_JF_ANCESTOR"))) ancestor;
 129   } GTY ((desc ("%1.type"))) value;
 130 };
 131
 132 /* All formal parameters in the program have a lattice associated with it
 133    computed by the interprocedural stage of IPCP.
 134    There are three main values of the lattice:
 135    IPA_TOP - unknown,
 136    IPA_BOTTOM - non constant,
 137    IPA_CONST_VALUE - simple scalar constant,
 138    Cval of formal f will have a constant value if all callsites to this
 139    function have the same constant value passed to f.
 140    Integer and real constants are represented as IPA_CONST_VALUE.  */
 141 enum ipa_lattice_type
 142 {
 143   IPA_BOTTOM,
 144   IPA_CONST_VALUE,
 145   IPA_TOP
 146 };
 147
 148 /* All formal parameters in the program have a cval computed by
 149    the interprocedural stage of IPCP. See enum ipa_lattice_type for
 150    the various types of lattices supported */
 151 struct ipcp_lattice
 152 {
 153   enum ipa_lattice_type type;
 154   tree constant;
 155 };
 156
 157 /* Structure describing a single formal parameter.  */
 158 struct ipa_param_descriptor
 159 {
 160   /* IPA-CP lattice.  */
 161   struct ipcp_lattice ipcp_lattice;
 162   /* PARAM_DECL of this parameter.  */
 163   tree decl;
 164   /* The parameter is used.  */
 165   unsigned used : 1;
 166 };
 167
 168 /* ipa_node_params stores information related to formal parameters of functions
 169    and some other information for interprocedural passes that operate on
 170    parameters (such as ipa-cp).  */
 171 struct ipa_node_params
 172 {
 173   /* Number of formal parameters of this function.  When set to 0,
 174      this function's parameters would not be analyzed by the different
 175      stages of IPA CP.  */
 176   int param_count;
 177   /* Whether this function is called with variable number of actual
 178      arguments.  */
 179   unsigned called_with_var_arguments : 1;
 180   /* Whether the param uses analysis has already been performed.  */
 181   unsigned uses_analysis_done : 1;
 182   /* Whether the function is enqueued in an ipa_func_list.  */
 183   unsigned node_enqueued : 1;
 184   /* Pointer to an array of structures describing individual formal
 185      parameters.  */
 186   struct ipa_param_descriptor *params;
 187   /* Only for versioned nodes this field would not be NULL,
 188      it points to the node that IPA cp cloned from.  */
 189   struct cgraph_node *ipcp_orig_node;
 190   /* Meaningful only for original functions.  Expresses the
 191      ratio between the direct calls and sum of all invocations of
 192      this function (given by profiling info).  It is used to calculate
 193      the profiling information of the original function and the versioned
 194      one.  */
 195   gcov_type count_scale;
 196 };
 197
 198 /* ipa_node_params access functions.  Please use these to access fields that
 199    are or will be shared among various passes.  */
 200
 201 /* Set the number of formal parameters. */
 202
 203 static inline void
 204 ipa_set_param_count (struct ipa_node_params *info, int count)
 205 {
 206   info->param_count = count;
 207 }
 208
 209 /* Return the number of formal parameters. */
 210
 211 static inline int
 212 ipa_get_param_count (struct ipa_node_params *info)
 213 {
 214   return info->param_count;
 215 }
 216
 217 /* Return the declaration of Ith formal parameter of the function corresponding
 218    to INFO.  Note there is no setter function as this array is built just once
 219    using ipa_initialize_node_params. */
 220
 221 static inline tree
 222 ipa_get_param (struct ipa_node_params *info, int i)
 223 {
 224   return info->params[i].decl;
 225 }
 226
 227 /* Return the used flag corresponding to the Ith formal parameter of
 228    the function associated with INFO.  */
 229
 230 static inline bool
 231 ipa_is_param_used (struct ipa_node_params *info, int i)
 232 {
 233   return info->params[i].used;
 234 }
 235
 236 /* Flag this node as having callers with variable number of arguments.  */
 237
 238 static inline void
 239 ipa_set_called_with_variable_arg (struct ipa_node_params *info)
 240 {
 241   info->called_with_var_arguments = 1;
 242 }
 243
 244 /* Have we detected this node was called with variable number of arguments? */
 245
 246 static inline bool
 247 ipa_is_called_with_var_arguments (struct ipa_node_params *info)
 248 {
 249   return info->called_with_var_arguments;
 250 }
 251
 252
 253
 254 /* ipa_edge_args stores information related to a callsite and particularly
 255    its arguments. It is pointed to by a field in the
 256    callsite's corresponding cgraph_edge.  */
 257 typedef struct GTY(()) ipa_edge_args
 258 {
 259   /* Number of actual arguments in this callsite.  When set to 0,
 260      this callsite's parameters would not be analyzed by the different
 261      stages of IPA CP.  */
 262   int argument_count;
 263   /* Array of the callsite's jump function of each parameter.  */
 264   struct ipa_jump_func GTY ((length ("%h.argument_count"))) *jump_functions;
 265 } ipa_edge_args_t;
 266
 267 /* ipa_edge_args access functions.  Please use these to access fields that
 268    are or will be shared among various passes.  */
 269
 270 /* Set the number of actual arguments. */
 271
 272 static inline void
 273 ipa_set_cs_argument_count (struct ipa_edge_args *args, int count)
 274 {
 275   args->argument_count = count;
 276 }
 277
 278 /* Return the number of actual arguments. */
 279
 280 static inline int
 281 ipa_get_cs_argument_count (struct ipa_edge_args *args)
 282 {
 283   return args->argument_count;
 284 }
 285
 286 /* Returns a pointer to the jump function for the ith argument.  Please note
 287    there is no setter function as jump functions are all set up in
 288    ipa_compute_jump_functions. */
 289
 290 static inline struct ipa_jump_func *
 291 ipa_get_ith_jump_func (struct ipa_edge_args *args, int i)
 292 {
 293   return &args->jump_functions[i];
 294 }
 295
 296 /* Vectors need to have typedefs of structures.  */
 297 typedef struct ipa_node_params ipa_node_params_t;
 298
 299 /* Types of vectors holding the infos.  */
 300 DEF_VEC_O (ipa_node_params_t);
 301 DEF_VEC_ALLOC_O (ipa_node_params_t, heap);
 302 DEF_VEC_O (ipa_edge_args_t);
 303 DEF_VEC_ALLOC_O (ipa_edge_args_t, gc);
 304
 305 /* Vector where the parameter infos are actually stored. */
 306 extern VEC (ipa_node_params_t, heap) *ipa_node_params_vector;
 307 /* Vector where the parameter infos are actually stored. */
 308 extern GTY(()) VEC (ipa_edge_args_t, gc) *ipa_edge_args_vector;
 309
 310 /* Return the associated parameter/argument info corresponding to the given
 311    node/edge.  */
 312 #define IPA_NODE_REF(NODE) (VEC_index (ipa_node_params_t, \
 313                                        ipa_node_params_vector, (NODE)->uid))
 314 #define IPA_EDGE_REF(EDGE) (VEC_index (ipa_edge_args_t, \
 315                                        ipa_edge_args_vector, (EDGE)->uid))
 316 /* This macro checks validity of index returned by
 317    ipa_get_param_decl_index function.  */
 318 #define IS_VALID_JUMP_FUNC_INDEX(I) ((I) != -1)
 319
 320 /* Creating and freeing ipa_node_params and ipa_edge_args.  */
 321 void ipa_create_all_node_params (void);
 322 void ipa_create_all_edge_args (void);
 323 void ipa_free_edge_args_substructures (struct ipa_edge_args *);
 324 void ipa_free_node_params_substructures (struct ipa_node_params *);
 325 void ipa_free_all_node_params (void);
 326 void ipa_free_all_edge_args (void);
 327 void ipa_create_all_structures_for_iinln (void);
 328 void ipa_free_all_structures_after_ipa_cp (void);
 329 void ipa_free_all_structures_after_iinln (void);
 330 void ipa_register_cgraph_hooks (void);
 331
 332 /* This function ensures the array of node param infos is big enough to
 333    accommodate a structure for all nodes and reallocates it if not.  */
 334
 335 static inline void
 336 ipa_check_create_node_params (void)
 337 {
 338   if (!ipa_node_params_vector)
 339     ipa_node_params_vector = VEC_alloc (ipa_node_params_t, heap,
 340                                         cgraph_max_uid);
 341
 342   if (VEC_length (ipa_node_params_t, ipa_node_params_vector)
 343       <= (unsigned) cgraph_max_uid)
 344     VEC_safe_grow_cleared (ipa_node_params_t, heap,
 345                            ipa_node_params_vector, cgraph_max_uid + 1);
 346 }
 347
 348 /* This function ensures the array of edge arguments infos is big enough to
 349    accommodate a structure for all edges and reallocates it if not.  */
 350
 351 static inline void
 352 ipa_check_create_edge_args (void)
 353 {
 354   if (!ipa_edge_args_vector)
 355     ipa_edge_args_vector = VEC_alloc (ipa_edge_args_t, gc,
 356                                       cgraph_edge_max_uid);
 357
 358   if (VEC_length (ipa_edge_args_t, ipa_edge_args_vector)
 359       <=  (unsigned) cgraph_edge_max_uid)
 360     VEC_safe_grow_cleared (ipa_edge_args_t, gc, ipa_edge_args_vector,
 361                            cgraph_edge_max_uid + 1);
 362 }
 363
 364 /* Returns true if the array of edge infos is large enough to accommodate an
 365    info for EDGE.  The main purpose of this function is that debug dumping
 366    function can check info availability without causing reallocations.  */
 367
 368 static inline bool
 369 ipa_edge_args_info_available_for_edge_p (struct cgraph_edge *edge)
 370 {
 371   return ((unsigned) edge->uid < VEC_length (ipa_edge_args_t,
 372                                              ipa_edge_args_vector));
 373 }
 374
 375 /* A function list element.  It is used to create a temporary worklist used in
 376    the propagation stage of IPCP. (can be used for more IPA optimizations)  */
 377 struct ipa_func_list
 378 {
 379   struct cgraph_node *node;
 380   struct ipa_func_list *next;
 381 };
 382
 383 /* ipa_func_list interface.  */
 384 struct ipa_func_list *ipa_init_func_list (void);
 385 void ipa_push_func_to_list_1 (struct ipa_func_list **, struct cgraph_node *,
 386                               struct ipa_node_params *);
 387 struct cgraph_node *ipa_pop_func_from_list (struct ipa_func_list **);
 388
 389 /* Add cgraph NODE to the worklist WL if it is not already in one.  */
 390
 391 static inline void
 392 ipa_push_func_to_list (struct ipa_func_list **wl, struct cgraph_node *node)
 393 {
 394   struct ipa_node_params *info = IPA_NODE_REF (node);
 395
 396   if (!info->node_enqueued)
 397     ipa_push_func_to_list_1 (wl, node, info);
 398 }
 399
 400 void ipa_analyze_node (struct cgraph_node *);
 401
 402 /* Function formal parameters related computations.  */
 403 void ipa_initialize_node_params (struct cgraph_node *node);
 404 bool ipa_propagate_indirect_call_infos (struct cgraph_edge *cs,
 405                                         VEC (cgraph_edge_p, heap) **new_edges);
 406
 407 /* Debugging interface.  */
 408 void ipa_print_node_params (FILE *, struct cgraph_node *node);
 409 void ipa_print_all_params (FILE *);
 410 void ipa_print_node_jump_functions (FILE *f, struct cgraph_node *node);
 411 void ipa_print_all_jump_functions (FILE * f);
 412
 413 /* Structure to describe transformations of formal parameters and actual
 414    arguments.  Each instance describes one new parameter and they are meant to
 415    be stored in a vector.  Additionally, most users will probably want to store
 416    adjustments about parameters that are being removed altogether so that SSA
 417    names belonging to them can be replaced by SSA names of an artificial
 418    variable.  */
 419 struct ipa_parm_adjustment
 420 {
 421   /* The original PARM_DECL itself, helpful for processing of the body of the
 422      function itself.  Intended for traversing function bodies.
 423      ipa_modify_formal_parameters, ipa_modify_call_arguments and
 424      ipa_combine_adjustments ignore this and use base_index.
 425      ipa_modify_formal_parameters actually sets this.  */
 426   tree base;
 427
 428   /* Type of the new parameter.  However, if by_ref is true, the real type will
 429      be a pointer to this type.  */
 430   tree type;
 431
 432   /* The new declaration when creating/replacing a parameter.  Created by
 433      ipa_modify_formal_parameters, useful for functions modifying the body
 434      accordingly. */
 435   tree reduction;
 436
 437   /* New declaration of a substitute variable that we may use to replace all
 438      non-default-def ssa names when a parm decl is going away.  */
 439   tree new_ssa_base;
 440
 441   /* If non-NULL and the original parameter is to be removed (copy_param below
 442      is NULL), this is going to be its nonlocalized vars value.  */
 443   tree nonlocal_value;
 444
 445   /* Offset into the original parameter (for the cases when the new parameter
 446      is a component of an original one).  */
 447   HOST_WIDE_INT offset;
 448
 449   /* Zero based index of the original parameter this one is based on.  (ATM
 450      there is no way to insert a new parameter out of the blue because there is
 451      no need but if it arises the code can be easily exteded to do so.)  */
 452   int base_index;
 453
 454   /* This new parameter is an unmodified parameter at index base_index. */
 455   unsigned copy_param : 1;
 456
 457   /* This adjustment describes a parameter that is about to be removed
 458      completely.  Most users will probably need to book keep those so that they
 459      don't leave behinfd any non default def ssa names belonging to them.  */
 460   unsigned remove_param : 1;
 461
 462   /* The parameter is to be passed by reference.  */
 463   unsigned by_ref : 1;
 464 };
 465
 466 typedef struct ipa_parm_adjustment ipa_parm_adjustment_t;
 467 DEF_VEC_O (ipa_parm_adjustment_t);
 468 DEF_VEC_ALLOC_O (ipa_parm_adjustment_t, heap);
 469
 470 typedef VEC (ipa_parm_adjustment_t, heap) *ipa_parm_adjustment_vec;
 471
 472 VEC(tree, heap) *ipa_get_vector_of_formal_parms (tree fndecl);
 473 void ipa_modify_formal_parameters (tree fndecl, ipa_parm_adjustment_vec,
 474                                    const char *);
 475 void ipa_modify_call_arguments (struct cgraph_edge *, gimple,
 476                                 ipa_parm_adjustment_vec);
 477 ipa_parm_adjustment_vec ipa_combine_adjustments (ipa_parm_adjustment_vec,
 478                                                  ipa_parm_adjustment_vec);
 479 void ipa_dump_param_adjustments (FILE *, ipa_parm_adjustment_vec, tree);
 480
 481 void ipa_prop_write_jump_functions (cgraph_node_set set);
 482 void ipa_prop_read_jump_functions (void);
 483 void ipa_update_after_lto_read (void);
 484
 485 /* From tree-sra.c:  */
 486 bool build_ref_for_offset (tree *, tree, HOST_WIDE_INT, tree, bool);
 487
 488 #endif /* IPA_PROP_H */